The field of art to which this invention pertains is aqueous dispersions of resinous compositions derived from epoxy resins, diphenols, diepoxides of polyoxyalkylene glycols, and organic diisocyanates, and to coating compositions made therefrom.
In view of the air pollution caused by organic solvents and to the increasing scarcity and cost of hydrocarbon solvents, there is a continuing search for new and improved coating compositions which can be dissolved or dispersed in water.
Water-borne coatings are being investigated for many uses, one use in particular being in the industrial maintenance field. Such coatings must be capable of drying to hard, corrosion resistant and solvent resistant films at ambient temperatures.
U.S. Pat. No. 4,315,044 describes a stable aqueous resin dispersion made from a self-emulsifying epoxy resin which when blended with an amine type curing agent and applied as a coating will cure at room temperature to form a continuous thermoset film. The self-emulsifying epoxy resin dispersion is made by (1) reacting a diglycidyl ether of a dihydric phenol and a diglycidyl ether of a polyoxyalkylene glycol with a dihydric phenol, and (2) dispersing the reaction product in water along with a water-immiscible aliphatic monoepoxide and a water-miscible solvent.